OLED is a light emitting element which basically includes an anode, a cathode, an Electron Hole (hole in short hereinafter) transmission layer located between the anode and the cathode, an electron transmission layer, and an organic light-emitting layer located between the hole transmission layer and the electron transmission layer. When a voltage is applied to the anode and the cathode, the hole and the electron are injected respectively from the anode and the cathode to the hole transmission layer and the electron transmission layer to join in the organic light-emitting layer and release an energy in a light form.
Compared with the conventional light-emitting elements the OLED has many advantages, such as lower electric consumption, flexible, faster reaction speed and the like, hence it is widely used in lighting fixtures, electronic indication lights and display backlight source and the like, and has gradually replaced traditional light-emitting elements such as LED, cold cathode tube or tungsten light bulb.
Conventional OLED structure, such as Taiwan Patent NO.I441554 entitled “OLED device with high color rendering” includes a substrate, a first conductive layer, a plurality of white light light-emitting layers and a second conductive layer. The first conductive layer is located on the substrate. The white light light-emitting layers are located on the first conductive layer, and the second conductive layer is located on the white light light-emitting layers. The white light light-emitting layers are complementary in spectrum, and at least one carrier regulation layer can be selectively placed between the white light light-emitting layers to further improve light-emitting efficiency and color rendering.
U.S. patent publication No. 2008/0165243 also discloses an OLED which includes a substrate, a plurality of OLED sets located on the substrate, a plurality of first wires located on the substrate, a plurality of spacers to separate the OLED sets, a plurality of first conductive blocks located on the substrate and a plurality of second conductive blocks located on the substrate. The OLED includes a first electrode, an organic light-emitting layer and a second electrode. The first wires are connected to the first electrodes of abutting OLED sets, the first conductive blocks are connected respectively to the first electrode of a first cluster, and the second conductive blocks are connected respectively to the second electrode of various clusters. The OLED module formed via the aforesaid technique requires a great deal of area for electrode wiring that results in too large size of elements.